Fluid cooled choke dielectric and coaxial cable dielectric

Abstract

The microwave antenna assembly includes a feedline electrically connected to an elongated shaft by a choke electrical connector. The feedline includes an inner conductor, an outer conductor, an elongated shaft and a choke electrical connector. The inner conductor is disposed in coaxial arrangement with the inner conductor and forms a dielectric supply lumen therebetween. The elongated shaft at least partially surrounding the feedline and form a dielectric return lumen therebetween. The choke electrical connector surrounds at least a portion of the feedline and electrically connects the feedline outer conductor to the elongated shaft. A low-loss dielectric fluid is supplied between the inner conductor and the outer conductor of the feedline and forms a dielectric barrier therebetween. The low-loss dielectric fluid also forms a dielectric barrier between the outer conductor of the feedline and the elongated shaft and the choke electrical connector forms a plurality of apertures extending therethrough, the apertures forming at least a portion of the dielectric return lumen.

What is claimed is: 
     
       1. A surgical microwave antenna assembly, comprising:
 a feedline having a length, the feedline including:
 an inner conductor; 
 an outer conductor in a coaxial arrangement with the inner conductor, the inner conductor and outer conductor forming a supply lumen therebetween; 
 
 an elongated shaft, at least partially surrounding the feedline, the elongated shaft and the feedline forming a return lumen therebetween; 
 a choke electrical connector including a substantially cylindrical inner surface surrounding the feedline over a portion of the length thereof and configured to electrically connect the outer conductor of the feedline to at least a portion of the elongated shaft; and 
 a low-loss dielectric fluid supplied between the inner conductor and the outer conductor of the feedline forming a dielectric barrier therebetween, the low-loss dielectric fluid also forming a dielectric barrier between the outer conductor of the feedline and the elongated shaft, 
 wherein the choke electrical connector forms a plurality of apertures extending therethrough, the apertures forming at least a portion of the return lumen. 
 
     
     
       2. The assembly of  claim 1 , wherein the supply lumen is disposed in fluid communication with the return lumen. 
     
     
       3. The assembly of  claim 2 , wherein the low-loss dielectric fluid is configured to absorb thermal energy from one of the inner conductor and the outer conductor. 
     
     
       4. The assembly of  claim 1 , further comprising: a radiating section connected to the distal end of the feedline and configured to radiate microwave energy at a predetermined microwave frequency. 
     
     
       5. The assembly of  claim 4 , wherein the radiating section is at least partially surrounded by a high-dielectric jacket. 
     
     
       6. The assembly of  claim 4 , wherein the choke electrical connector forms a Faraday shield and is configured to shunt electromagnetic energy radiating proximally from the radiating section. 
     
     
       7. The assembly of  claim 5 , wherein the Faraday shield formed by the choke electrical connector is configured to shunt electromagnetic energy at the predetermined microwave frequency. 
     
     
       8. The assembly of  claim 6 , wherein the predetermined microwave frequency is about 915 MHz. 
     
     
       9. The assembly of  claim 6 , wherein the predetermined microwave frequency is about 2.54 GHz. 
     
     
       10. The assembly of  claim 1 , wherein the plurality of apertures of the choke electrical connector defines a plurality of fluid pathways in a direction along and about a longitudinal axis of the inner conductor. 
     
     
       11. The assembly of  claim 1 , wherein a spacing of the apertures of the choke electrical connector is selected to determine frequencies that are effectively shunted by the choke electrical connector. 
     
     
       12. A surgical microwave ablation system, comprising:
 a microwave signal generator; 
 a low-loss dielectric fluid supply; and 
 a surgical microwave antenna assembly, including:
 a feedline having a length, the feedline including:
 an inner conductor; 
 an outer conductor in a coaxial arrangement with the inner conductor, the inner conductor and outer conductor forming a supply lumen therebetween; 
 
 an elongated shaft, at least partially surrounding the feedline, the elongated shaft and the feedline forming a return lumen therebetween; 
 a choke electrical connector including an annular surface defining an opening therethrough, the annular surface configured to electrically connect the outer conductor of the feedline to at least a portion of the elongated shaft; and 
 a low-loss dielectric fluid supplied between the inner conductor and the outer conductor of the feedline and forming a dielectric barrier therebetween, the low-loss dielectric fluid also forming a dielectric barrier between the outer conductor of the feedline and the elongated shaft, 
 
 wherein the low-loss dielectric fluid supply provides the low-loss dielectric fluid to the supply lumen, and wherein the choke electrical connector of the surgical microwave antenna assembly forms a plurality of apertures extending therethrough, the apertures forming at least a portion of the return lumen. 
 
     
     
       13. The system of  claim 12 , wherein the low-loss dielectric fluid supply and the return lumen are in fluid communication through the supply lumen. 
     
     
       14. The system of  claim 13 , wherein the low-loss dielectric fluid is configured to absorb thermal energy from one of the inner conductor and the outer conductor. 
     
     
       15. The system of  claim 12 , wherein the surgical microwave antenna assembly further includes:
 a radiating section connected to the distal end of the feedline and configured to radiate microwave energy at a predetermined microwave frequency, 
 wherein the microwave signal generator generates the microwave energy signal and the feedline electrically connects the microwave signal generator to the radiating section. 
 
     
     
       16. The system of  claim 15 , wherein the choke electrical connector of the surgical microwave antenna assembly forms a Faraday shield and is configured to shunt electromagnetic energy radiating proximally from the radiating section. 
     
     
       17. The system of  claim 16 , wherein the radiating section of the surgical microwave antenna assembly is at least partially surrounded by a high-dielectric jacket. 
     
     
       18. The system of  claim 16 , wherein the Faraday shield formed by the choke electrical connector is configured to shunt electromagnetic energy at the predetermined microwave frequency. 
     
     
       19. The system of  claim 18 , wherein the predetermined microwave frequency is about 915 MHz. 
     
     
       20. The system of  claim 12 , wherein the plurality of apertures of the choke electrical connector defines a plurality of fluid pathways in a direction along and about a longitudinal axis of the inner conductor. 
     
     
       21. The system of  claim 12 , wherein a diameter of the apertures of the choke electrical connector is selected to determine frequencies that are effectively shunted by the choke electrical connector. 
     
     
       22. A surgical microwave antenna assembly, comprising:
 a feedline having a length, the feedline including:
 an inner conductor; 
 an outer conductor in a coaxial arrangement with the inner conductor, the inner conductor and outer conductor forming a supply lumen therebetween; 
 
 an elongated shaft, at least partially surrounding the feedline, the elongated shaft and the feedline forming a return lumen therebetween; and 
 a choke electrical connector including an inner surface defining an opening therethrough, the inner surface circumferentially disposed in contact with the feedline over a portion of the length thereof and configured to electrically connect the outer conductor of the feedline to at least a portion of the elongated shaft, wherein the choke electrical connector forms a plurality of apertures extending therethrough, the apertures forming at least a portion of the return lumen, wherein a diameter of the apertures is selected to be less than a wavelength of a microwave signal radiated by the surgical microwave antenna assembly during operation thereof.